Add a driver option -ivfsoverlay

Reads the description of a virtual filesystem from a file and overlays
it over the real file system.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@202176 91177308-0d34-0410-b5e6-96231b3b80d8

24 files changed, 182 insertions, 1 deletions

diff --git a/include/clang/Basic/DiagnosticFrontendKinds.td b/include/clang/Basic/DiagnosticFrontendKinds.td
index 21809ad63f..2b36d38a3f 100644
--- a/include/clang/Basic/DiagnosticFrontendKinds.td
+++ b/include/clang/Basic/DiagnosticFrontendKinds.td
@@ -158,4 +158,9 @@ def warn_module_config_macro_undef : Warning<
   InGroup<ConfigMacros>;
 def note_module_def_undef_here : Note<
   "macro was %select{defined|#undef'd}0 here">;
+
+def err_missing_vfs_overlay_file : Error<
+  "virtual filesystem overlay file '%0' not found">, DefaultFatal;
+def err_invalid_vfs_overlay : Error<
+  "invalid virtual filesystem overlay file '%0'">, DefaultFatal;
 }
diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index d2192586d9..019850be3d 100644
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -966,6 +966,8 @@ def iwithsysroot : JoinedOrSeparate<["-"], "iwithsysroot">, Group<clang_i_Group>
   HelpText<"Add directory to SYSTEM include search path, "
            "absolute paths are relative to -isysroot">, MetaVarName<"<directory>">,
   Flags<[CC1Option]>;
+def ivfsoverlay : JoinedOrSeparate<["-"], "ivfsoverlay">, Group<clang_i_Group>, Flags<[CC1Option]>,
+  HelpText<"Overlay the virtual filesystem described by file over the real file system">;
 def i : Joined<["-"], "i">, Group<i_Group>;
 def keep__private__externs : Flag<["-"], "keep_private_externs">;
 def l : JoinedOrSeparate<["-"], "l">, Flags<[LinkerInput, RenderJoined]>;
diff --git a/include/clang/Lex/HeaderSearchOptions.h b/include/clang/Lex/HeaderSearchOptions.h
index b471b8cafe..5abcdad2d5 100644
--- a/include/clang/Lex/HeaderSearchOptions.h
+++ b/include/clang/Lex/HeaderSearchOptions.h
@@ -129,6 +129,9 @@ public:
   /// \brief The set of user-provided module-map-files.
   llvm::SetVector<std::string> ModuleMapFiles;
 
+  /// \brief The set of user-provided virtual filesystem overlay files.
+  std::vector<std::string> VFSOverlayFiles;
+
   /// Include the compiler builtin includes.
   unsigned UseBuiltinIncludes : 1;
 
@@ -172,6 +175,10 @@ public:
   void AddSystemHeaderPrefix(StringRef Prefix, bool IsSystemHeader) {
     SystemHeaderPrefixes.push_back(SystemHeaderPrefix(Prefix, IsSystemHeader));
   }
+
+  void AddVFSOverlayFile(StringRef Name) {
+    VFSOverlayFiles.push_back(Name);
+  }
 };
 
 } // end namespace clang
diff --git a/lib/Basic/VirtualFileSystem.cpp b/lib/Basic/VirtualFileSystem.cpp
index 881e166395..539cbb7409 100644
--- a/lib/Basic/VirtualFileSystem.cpp
+++ b/lib/Basic/VirtualFileSystem.cpp
@@ -761,7 +761,7 @@ error_code VFSFromYAML::openFileForRead(const Twine &Path,
   if (!F) // FIXME: errc::not_a_file?
     return error_code(errc::invalid_argument, system_category());
 
-  return ExternalFS->openFileForRead(Path, Result);
+  return ExternalFS->openFileForRead(F->getExternalContentsPath(), Result);
 }
 
 IntrusiveRefCntPtr<FileSystem>
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 4ef5cfef7c..ad2d37cc29 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1020,6 +1020,10 @@ static void ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args) {
        I != E; ++I)
     Opts.AddSystemHeaderPrefix((*I)->getValue(),
                                (*I)->getOption().matches(OPT_isystem_prefix));
+
+  for (arg_iterator I = Args.filtered_begin(OPT_ivfsoverlay),
+       E = Args.filtered_end(); I != E; ++I)
+    Opts.AddVFSOverlayFile((*I)->getValue());
 }
 
 void CompilerInvocation::setLangDefaults(LangOptions &Opts, InputKind IK,
diff --git a/lib/Frontend/FrontendAction.cpp b/lib/Frontend/FrontendAction.cpp
index 72377d8457..6cfa12168d 100644
--- a/lib/Frontend/FrontendAction.cpp
+++ b/lib/Frontend/FrontendAction.cpp
@@ -211,6 +211,32 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     return true;
   }
 
+  if (!CI.getHeaderSearchOpts().VFSOverlayFiles.empty()) {
+    IntrusiveRefCntPtr<vfs::OverlayFileSystem>
+        Overlay(new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
+    // earlier vfs files are on the bottom
+    const std::vector<std::string> &Files =
+        CI.getHeaderSearchOpts().VFSOverlayFiles;
+    for (std::vector<std::string>::const_iterator I = Files.begin(),
+                                                  E = Files.end();
+         I != E; ++I) {
+      OwningPtr<llvm::MemoryBuffer> Buffer;
+      if (llvm::errc::success != llvm::MemoryBuffer::getFile(*I, Buffer)) {
+        CI.getDiagnostics().Report(diag::err_missing_vfs_overlay_file) << *I;
+        goto failure;
+      }
+
+      IntrusiveRefCntPtr<vfs::FileSystem> FS =
+          vfs::getVFSFromYAML(Buffer.take(), /*DiagHandler*/0);
+      if (!FS.getPtr()) {
+        CI.getDiagnostics().Report(diag::err_invalid_vfs_overlay) << *I;
+        goto failure;
+      }
+      Overlay->pushOverlay(FS);
+    }
+    CI.setVirtualFileSystem(Overlay);
+  }
+
   // Set up the file and source managers, if needed.
   if (!CI.hasFileManager())
     CI.createFileManager();
diff --git a/test/Driver/vfsoverlay.c b/test/Driver/vfsoverlay.c
new file mode 100644
index 0000000000..6ae494544f
--- /dev/null
+++ b/test/Driver/vfsoverlay.c
@@ -0,0 +1,5 @@
+// RUN: %clang -ivfsoverlay foo.h -### %s 2>&1 | FileCheck %s
+// CHECK: "-ivfsoverlay" "foo.h"
+
+// RUN: not %clang -ivfsoverlay foo.h %s 2>&1 | FileCheck -check-prefix=CHECK-MISSING %s
+// CHECK-MISSING: virtual filesystem overlay file 'foo.h' not found
diff --git a/test/VFS/Inputs/actual_header.h b/test/VFS/Inputs/actual_header.h
new file mode 100644
index 0000000000..f61e58620c
--- /dev/null
+++ b/test/VFS/Inputs/actual_header.h
@@ -0,0 +1 @@
+void bar(void);
diff --git a/test/VFS/Inputs/actual_module.map b/test/VFS/Inputs/actual_module.map
new file mode 100644
index 0000000000..282dac37c7
--- /dev/null
+++ b/test/VFS/Inputs/actual_module.map
@@ -0,0 +1,4 @@
+module not_real {
+  header "not_real.h"
+  export *
+}
diff --git a/test/VFS/Inputs/include_real.h b/test/VFS/Inputs/include_real.h
new file mode 100644
index 0000000000..0750c65272
--- /dev/null
+++ b/test/VFS/Inputs/include_real.h
@@ -0,0 +1 @@
+#include "real.h"
diff --git a/test/VFS/Inputs/invalid-yaml.yaml b/test/VFS/Inputs/invalid-yaml.yaml
new file mode 100644
index 0000000000..2a6c6667ce
--- /dev/null
+++ b/test/VFS/Inputs/invalid-yaml.yaml
@@ -0,0 +1,4 @@
+{
+  'version': 0,
+  'roots': []
+]
diff --git a/test/VFS/Inputs/missing-key.yaml b/test/VFS/Inputs/missing-key.yaml
new file mode 100644
index 0000000000..5d18c244ee
--- /dev/null
+++ b/test/VFS/Inputs/missing-key.yaml
@@ -0,0 +1,4 @@
+{
+  'version': 0,
+  'roots': [ { 'name' : 'foo', 'external-contents': 'bar' } ]
+}
diff --git a/test/VFS/Inputs/public_header.h b/test/VFS/Inputs/public_header.h
new file mode 100644
index 0000000000..471107762b
--- /dev/null
+++ b/test/VFS/Inputs/public_header.h
@@ -0,0 +1 @@
+void from_framework(void);
diff --git a/test/VFS/Inputs/unknown-key.yaml b/test/VFS/Inputs/unknown-key.yaml
new file mode 100644
index 0000000000..ec7d8261d9
--- /dev/null
+++ b/test/VFS/Inputs/unknown-key.yaml
@@ -0,0 +1,5 @@
+{
+  'version': 0,
+  'unknown-key': 'value',
+  'roots': []
+}
diff --git a/test/VFS/Inputs/unknown-value.yaml b/test/VFS/Inputs/unknown-value.yaml
new file mode 100644
index 0000000000..4e90b2134c
--- /dev/null
+++ b/test/VFS/Inputs/unknown-value.yaml
@@ -0,0 +1,5 @@
+{
+  'version': 0,
+  'case-sensitive': 'Maybe?',
+  'roots': []
+}
diff --git a/test/VFS/Inputs/vfsoverlay.yaml b/test/VFS/Inputs/vfsoverlay.yaml
new file mode 100644
index 0000000000..331ed33316
--- /dev/null
+++ b/test/VFS/Inputs/vfsoverlay.yaml
@@ -0,0 +1,21 @@
+{
+  'version': 0,
+  'roots': [
+    { 'name': 'OUT_DIR', 'type': 'directory',
+      'contents': [
+        { 'name': 'not_real.h', 'type': 'file',
+          'external-contents': 'INPUT_DIR/actual_header.h'
+        },
+        { 'name': 'module.map', 'type': 'file',
+          'external-contents': 'INPUT_DIR/actual_module.map'
+        },
+        { 'name': 'include_real.h', 'type': 'file',
+          'external-contents': 'INPUT_DIR/include_real.h'
+        },
+        { 'name': 'SomeFramework.framework/Headers/public_header.h', 'type': 'file',
+          'external-contents': 'INPUT_DIR/public_header.h'
+        }
+      ]
+    }
+  ]
+}
diff --git a/test/VFS/framework-import.m b/test/VFS/framework-import.m
new file mode 100644
index 0000000000..b40bc549c0
--- /dev/null
+++ b/test/VFS/framework-import.m
@@ -0,0 +1,9 @@
+// RUN: sed -e "s:INPUT_DIR:%S/Inputs:g" -e "s:OUT_DIR:%t:g" %S/Inputs/vfsoverlay.yaml > %t.yaml
+// RUN: %clang_cc1 -Werror -F %t -ivfsoverlay %t.yaml -fsyntax-only %s
+// REQUIRES: shell
+
+#import <SomeFramework/public_header.h>
+
+void foo() {
+  from_framework();
+}
diff --git a/test/VFS/implicit-include.c b/test/VFS/implicit-include.c
new file mode 100644
index 0000000000..acf665bee2
--- /dev/null
+++ b/test/VFS/implicit-include.c
@@ -0,0 +1,7 @@
+// RUN: sed -e "s:INPUT_DIR:%S/Inputs:g" -e "s:OUT_DIR:%t:g" %S/Inputs/vfsoverlay.yaml > %t.yaml
+// RUN: %clang_cc1 -Werror -ivfsoverlay %t.yaml -I %t -include "not_real.h" -fsyntax-only %s
+// REQUIRES: shell
+
+void foo() {
+  bar();
+}
diff --git a/test/VFS/include-mixed-real-and-virtual.c b/test/VFS/include-mixed-real-and-virtual.c
new file mode 100644
index 0000000000..e1f5f952cd
--- /dev/null
+++ b/test/VFS/include-mixed-real-and-virtual.c
@@ -0,0 +1,14 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+// RUN: echo "void baz(void);" > %t/real.h
+// RUN: sed -e "s:INPUT_DIR:%S/Inputs:g" -e "s:OUT_DIR:%t:g" %S/Inputs/vfsoverlay.yaml > %t.yaml
+// RUN: %clang_cc1 -Werror -ivfsoverlay %t.yaml -I %t -fsyntax-only %s
+// REQUIRES: shell
+
+#include "not_real.h"
+#include "real.h"
+
+void foo() {
+  bar();
+  baz();
+}
diff --git a/test/VFS/include-real-from-virtual.c b/test/VFS/include-real-from-virtual.c
new file mode 100644
index 0000000000..65707b5516
--- /dev/null
+++ b/test/VFS/include-real-from-virtual.c
@@ -0,0 +1,12 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+// RUN: echo "void baz(void);" > %t/real.h
+// RUN: sed -e "s:INPUT_DIR:%S/Inputs:g" -e "s:OUT_DIR:%t:g" %S/Inputs/vfsoverlay.yaml > %t.yaml
+// RUN: %clang_cc1 -Werror -ivfsoverlay %t.yaml -I %t -fsyntax-only %s
+// REQUIRES: shell
+
+#include "include_real.h"
+
+void foo() {
+  baz();
+}
diff --git a/test/VFS/include-virtual-from-real.c b/test/VFS/include-virtual-from-real.c
new file mode 100644
index 0000000000..c8f6059608
--- /dev/null
+++ b/test/VFS/include-virtual-from-real.c
@@ -0,0 +1,12 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+// RUN: echo '#include "not_real.h"' > %t/include_not_real.h
+// RUN: sed -e "s:INPUT_DIR:%S/Inputs:g" -e "s:OUT_DIR:%t:g" %S/Inputs/vfsoverlay.yaml > %t.yaml
+// RUN: %clang_cc1 -Werror -ivfsoverlay %t.yaml -I %t -fsyntax-only %s
+// REQUIRES: shell
+
+#include "include_not_real.h"
+
+void foo() {
+  bar();
+}
diff --git a/test/VFS/include.c b/test/VFS/include.c
new file mode 100644
index 0000000000..8cd04dd452
--- /dev/null
+++ b/test/VFS/include.c
@@ -0,0 +1,9 @@
+// RUN: sed -e "s:INPUT_DIR:%S/Inputs:g" -e "s:OUT_DIR:%t:g" %S/Inputs/vfsoverlay.yaml > %t.yaml
+// RUN: %clang_cc1 -Werror -I %t -ivfsoverlay %t.yaml -fsyntax-only %s
+// REQUIRES: shell
+
+#include "not_real.h"
+
+void foo() {
+  bar();
+}
diff --git a/test/VFS/module-import.m b/test/VFS/module-import.m
new file mode 100644
index 0000000000..80f0ea58f1
--- /dev/null
+++ b/test/VFS/module-import.m
@@ -0,0 +1,9 @@
+// RUN: sed -e "s:INPUT_DIR:%S/Inputs:g" -e "s:OUT_DIR:%t:g" %S/Inputs/vfsoverlay.yaml > %t.yaml
+// RUN: %clang_cc1 -Werror -fmodules -fmodules-cache-path=%t -ivfsoverlay %t.yaml -I %t -fsyntax-only %s
+// REQUIRES: shell
+
+@import not_real;
+
+void foo() {
+  bar();
+}
diff --git a/test/VFS/parse-errors.c b/test/VFS/parse-errors.c
new file mode 100644
index 0000000000..7194efc65a
--- /dev/null
+++ b/test/VFS/parse-errors.c
@@ -0,0 +1,14 @@
+// RUN: not %clang_cc1 -ivfsoverlay %S/Inputs/invalid-yaml.yaml -fsyntax-only %s 2>&1 | FileCheck %s
+// CHECK: invalid virtual filesystem overlay file
+
+// RUN: not %clang_cc1 -ivfsoverlay %S/Inputs/missing-key.yaml -fsyntax-only %s 2>&1 | FileCheck -check-prefix=CHECK-MISSING-TYPE %s
+// CHECK-MISSING-TYPE: missing key 'type'
+// CHECK-MISSING-TYPE: invalid virtual filesystem overlay file
+
+// RUN: not %clang_cc1 -ivfsoverlay %S/Inputs/unknown-key.yaml -fsyntax-only %s 2>&1 | FileCheck -check-prefix=CHECK-UNKNOWN-KEY %s
+// CHECK-UNKNOWN-KEY: unknown key
+// CHECK-UNKNOWN-KEY: invalid virtual filesystem overlay file
+
+// RUN: not %clang_cc1 -ivfsoverlay %S/Inputs/unknown-value.yaml -fsyntax-only %s 2>&1 | FileCheck -check-prefix=CHECK-UNKNOWN-VALUE %s
+// CHECK-UNKNOWN-VALUE: expected boolean value
+// CHECK-UNKNOWN-VALUE: invalid virtual filesystem overlay file